1. Field of the Application
The invention relates to the manufacture of metal wire, and more particularly, to machines for multidie nonslip drawing of wire products.
The invention is applicable to dry or wet drawing of wire and other products from various metals and alloys.
2. Description of the Prior Art
There are known several types of machines for multidie drawing, which operate with no slipping of wire on draw blocks.
These types include looping back-pull drawing machines, double-deck machines and cumulative type wire-drawing machines.
For example, there is known a machine for multidie nonslip drawing, developed by the firm Reinking Maschinenbau, with a drive composed of a standard three-phase electric motor and a positive-displacement hydraulic pump (see "Stahl und Eisen", 1976, no. 1 9, p. 927). The machine has a number of draw blocks driven from regulated hydraulic motors, die-head blocks with dies being mounted in front of each draw block, the drawing speed being continuously adjustable between zero and the maximum value.
The drawing speed is adjusted by means of a governor which varies the speed as a function of drawing forces at constant power input.
In this manner, the drawing speed for wire of any diameter sets itself at a maximum value determined by the power rating of the motor. The machine is provided with individual drives for each draw block.
Among the disadvantages of the aforementioned machine are:
the necessity for individual re-adjustment of each hydraulic motor on change of drawing route; large size of the machine because of the individual drives for each draw block; large metal requirements for manufacturing the machine; small drawing speeds and short service life of the positive-displacement hydraulic drive.
There is known a multidie nonslip cumulative drawing machine with wire storage on draw blocks. The machine comprises several draw blocks, each mounted on a separate shaft and coupled to a hydraulic transmission, or a hydraulic clutch, placed on the shaft of an asynchronous electric motor. Die-head blocks with dies are arranged in front of each draw block. The machine is equipped with decoiling and coiling devices.
The disadvantages of the machine described above are as follows: each drawing unit is complex and bulky because of a large number of series-arranged elements of the draw block drive components, large overall dimensions of the drawing machine because of individually driven draw blocks, large metal requirement for manufacturing the machine; no engaging speed, so that a wire is engaged by operating the machine in inching duty; inclusion of gear boxes in the drive of each draw block, which requires individual re-adjustment of the gear boxes when changing over to other drawing speeds.
Many types of hydraulic transformers have been proposed, wherein the speed of the output shaft is governed by actuating a valve which shuts off a flow of liquid in a circulation circuit (see, for example, B. A. Gavrilenko and I. F. Semichastnov, "Hydrodynamic Clutches and Transformers" /in Russian/, Moscow, "Machinostroeniye" Publishers, 1969, p. 283).
Among other known types of hydraulic transformers, one closely similar in engineering arrangement is a hydraulic transformer employed in a hydraulic reversible transmission according to U.S. Pat. No. 3,677,004 (FIG. 6).
The valve placed inside a cavity of the hydraulic transformer and shutting off the flow of the liquid in the circulation circuit, is connected to rods of several hydraulic cylinders arranged circularly with respect to the axis of rotation of elements of the hydraulic transformer. Rod cavities of the hydraulic cylinders communicate with the cavity of the hydraulic transformer, so that the pressure of the liquid acts upon the valve and the pistons of the hydraulic cylinders to maintain the valve open, this action being supported by springs placed in the rod cavities of the hydraulic cylinders.
The motion of the valve is controlled by supplying the liquid into the piston cavity from an independent source. The disadvantage inherent in said hydraulic transformer are: inclusion of several hydraulic cylinder actuators; non-simultaneous motion of all the hydraulic cylinders; complicated design; the valve opens when the controlling pressure is removed, this resulting, when the motor is in operation, in a rotation of the output shaft, which presents a measure of hazard; necessity for an extraneous source of the working liquid under pressure for controlling said valve.